Letter to Gordon Armstrong Patent Suspension Co. Ltd. specifying requirements for a double-acting damper.
| Identifier | ExFiles\Box 152\2\ scan0127 | |
| Date | 1st December 1938 | |
| 1293 Experimental Dept. Rm {William Robotham - Chief Engineer} /AFM. {Anthony F. Martindale} 8/MH. {M. Huckerby} 1st. December 1938. Gordon Armstrong Patent Suspension Co. Ltd., Waltham Works, Beverley, E.Yorks. Dear Sirs, Double Acting Damper. As you are doubtless aware we are proposing to use your smallest shock damper as a dashpot. The original samples supplied by you had only an adjustable orifice in the passage between the two cylinders. This is all we require. The latest dampers supplied now have a valve with springs and this is not at all desirable. We can use the valve by making the springs solid and allowing a certain leak, but it is not so convenient. What we require is the original "leak" damper. Will you please arrange that future supplies shall be of this type. The setting of the leak as the dampers arrive at this Works should be as follows:- With a 2½ lb. weight hung on the end of the arm, the said end should move 1½ inches in 3½ seconds. Owing to the friction in the damper, it is necessary to neutralize this by weights on the end of the arm, before the leak is timed. The friction is variable but may amount to 6 lbs. The thin oil you have been supplying in these dampers is satisfactory and should not be changed to any other type, when we order the 200 dampers. | ||
From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).